1. Field of the Invention
This invention relates to a device for preventing erroneous insertion of a plurality of print substrates into corresponding connectors in a rack.
2. Description of the Prior Art
In the case of inserting a plurality of print substrates into corresponding connectors in a rack and constructing a unit or removing the print substrates from the connectors for the purpose of effecting inspection, repair or the like thereof and then treating and subsequently inserting these print substrates again into the corresponding connectors, these print substrates are the same in shape with each other, so that there is a risk of each print substrate being erroneously inserted into a connector other than the corresponding connector. As a result, electronic parts and elements mounted on the print substrate become subjected to unexpected short-circuit or the like or troubles are induced in an electric circuit printed on the other print substrate.
In the case of inserting a plurality of print substrates into corresponding connectors provided in a rack, following measures have been made to overcome the above mentioned problem, that is,
(1) Connectors and print substrates corresponding with each other are provided beforehand with numbers, marks or the like and after confirming these numbers, marks or the like each print substrate is inserted into corresponding connector in the rack, and PA1 (2) Corresponding connector and print substrate are memorized and then the print substrates are inserted into the connectors in succession.
But, after the print substrates have been subjected to treatments such as adjustment, inspection, repair or the like, if confirmation to be taken in the above mentioned measures (1) and (2) is neglected, electronic parts mounted on the print substrates are subjected to short-circuits and unnecessary voltages, thereby burning the electronic elements into damage and inducing troubles to the electric circuit printed on the other print substrates.
In order to eliminate the above mentioned drawback, a device for optically detecting erroneous insertion of a plurality of print substrates into connectors in a rack has been proposed. In this device, respective print substrates are provided at their rear end portions as viewed in their inserting direction with openings which are aligned with each other when respective print substrates are correctly inserted into corresponding connectors in the rack. At the left and right sides of the rack are arranged a light emitting element and light receiving element opposed to the openings of the print substrates concerned. After all of the print substrates are correctly inserted into the corresponding connectors in the rack, the openings are aligned with each other and light emitted from the light emitting element passes through the openings in respective print substrates to the light receiving element to turn on a lamp connected thereto. On the contrary, if the lamp is not turned on, it shows that the erroneous insertion of the print substrates is present. But, such conventional device has the disadvantage that the erroneous insertion of the print substrates could not be detected unless all of the print substrates have been inserted into corresponding connectors in the rack and hence it is impossible to ascertain whether or not print substrates are correctly inserted into corresponding connector one by one, whereby electronic parts mounted on the print substrates become burnt into damage and there occurs troubles in electric circuits printed on the other print substrate, and that if the erroneous insertion is detected, all of the print substrates must be removed from the rack and then inserted again into corresponding connectors and hence the device is troublesome in operation.